Imaging lens device and portable apparatus having imaging function

ABSTRACT

A portable apparatus includes a body accommodating an imaging plane, and a lens device providing a light beam path and including lens elements arranged along and coaxially with the path. The second lens element next to the most outwardly located first one is reciprocally rotational between a first position, at which the second element is coaxial with the path, and a second position, at which the second element is out from the path. The first element is provide on a cylindrical unit having a diameter surrounding the first and second positions of the second element, is reciprocally movable with the unit along the optical axis of the path, and is moved to approach to the plane while the second element is in the second position and to shorten a distance between the first element and the plane in comparison with that when the second element is in the first position.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based upon and claims the benefit of priority fromprior Japanese Patent Application No. 2003-375808, filed Nov. 5, 2003,the entire contents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an imaging lens device and a portableapparatus having imaging function.

2. Description of the Related Art

A portable apparatus having imaging function, such as a camera, uses animaging lens device. The imaging lens device provides an imaging lightbeam path for leading incident light beam to a predetermined imagingplane, and includes a plurality of lens elements arranged along andbeing coaxial with the imaging light beam path for focusing the incidentlight beam on the predetermined imaging plane.

Since the imaging lens device includes the plural lens elements arrangedalong the imaging light beam path, the longitudinal length of theimaging lens device is relatively long so that the imaging lens devicelargely projects out from the body of the portable apparatus.

In such a conventional portable apparatus as described above, thelargely projected imaging lens device deteriorates the portability ofthe conventional portable apparatus. In order to improve the portabilityof the conventional portable apparatus, Japanese Patent ApplicationKOKAI Publication No. 2000-23002, published on Jan. 21, 2000, disclosesthat to make one lens element, which is located nearer to thepredetermined imaging plane than the lens element located most away fromthe predetermined imaging plane, being movable between a first position,at which the one lens element is coaxially located in the imaging lightbeam path, and a second position, at which the one lens element is movedsideward and away from the imaging light beam path. The sideward movablelens element is located at the first position when the imaging lensdevice is used for focusing the incident light on the predeterminedimaging plane, and the sideward movable lens element is located at thesecond position when the imaging lens device is not used for focusingthe incident light on the predetermined imaging plane. While thesideward movable lens element is located at the second position, themost away located lens element can be moved toward the predeterminedimaging plane by the longitudinal length of the sideward movable lenselement so that the longitudinal length of the imaging lens device canbe shortened.

However, in this published portable apparatus, it is difficult toarrange the sideward movable lens element to be accurately coaxial withthe imaging light beam path when the sideward movable lens is moved fromthe second position to the first position and stays at the firstposition.

BRIEF SUMMARY OF THE INVENTION

According to one aspect of the invention, an imaging lens deviceprovides an imaging light beam path for leading incident light beam to apredetermined imaging plane and includes a plurality of lens elementsarranged along and being coaxial with the imaging light beam path forfocusing the incident light beam on the predetermined imaging plane. Atleast one of the plural lens elements excluding a lens element locatedmost away from the predetermined imaging plane, is reciprocallyrotational around a rotation center located in the outside of theimaging light beam path between a first position, at which the at leastone lens element is coaxially arranged in the imaging light beam path,and a second position, at which the at least one lens element is outfrom the imaging light beam path. The most away located lens element isreciprocally movable along the imaging light beam path. The most awaylocated lens element is moved to approach to the predetermined imagingplane while the at least one lens element is located in the secondposition, and shortens a distance between the most away located lenselement and the predetermined imaging plane in comparison with thedistance between them when the at least one lens element is located inthe first position.

According to another aspect of the invention, a portable apparatushaving an imaging function, comprises: a portable apparatus main bodyhaving an inner space accommodating an imaging plane; and an imaginglens device, which provides an imaging light beam path for leadingincident light beam to the imaging plane and includes a plurality oflens elements arranged along and being coaxial with the imaging lightbeam path for focusing the incident light beam on the imaging plane. Atleast one of the plural lens elements excluding a lens element locatedmost away from the imaging plane, is reciprocally rotational around arotation center located in the outside of the imaging light beam pathbetween a first position, at which the at least one lens element iscoaxially arranged in the imaging light beam path, and a secondposition, at which the at least one lens element is out from the imaginglight beam path. The imaging lens device includes a cylindrical unitbeing provided with the most away located lens element, having adiameter surrounding the first and second positions of the at least onelens element, and being reciprocally movable together with the most awaylocated lens element along the optical axis of the imaging light beampath. And, the most away located lens element is moved to approach tothe imaging plane while the at least one lens element is located in thesecond position, and shortens a distance between the most away locatedlens element and the imaging plane in comparison with the distancebetween them when the at least one lens element is located in the firstposition.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

The accompanying drawings, which are incorporated in and constitute apart of the specification, illustrate an embodiment of the invention,and together with the general description given above and the detaileddescription of the embodiment given below, serve to explain theprinciples of the invention.

FIG. 1 is a perspective view showing a camera as a portable apparatushaving an imaging function, according to an embodiment of the presentinvention, in which an imaging lens device of the camera is in a usestate;

FIG. 2 is a vertical cross sectional view of the camera shown in FIG. 1along the optical axis of the imaging lens device; and

FIG. 3 is a vertical cross sectional view of the camera in which theimaging lens device is in a non-use state.

DETAILED DESCRIPTION OF THE INVENTION

A portable apparatus having an imaging function and according to oneembodiment of the present invention is a thin type digital camera. Asshown in FIGS. 1 to 3, the portable apparatus has a main body 1 of athin type rectangular case, each of the substantially flat front andrear walls thereof being in parallel to each other. An imaging lensdevice 2 is provided to the front wall of the main body 1 and is movablebetween a projecting position, at which the imaging lens device 2projects out from the front wall as shown in FIGS. 1 and 2, and anretracted position, at which the imaging lens device 2 is retracted intothe inner space of the main body 1 as shown in FIG. 3. The main body 1accommodates an imaging plane 3 a in the inner space.

In this embodiment, the imaging plane 3 a is located in a predeterminedposition near to the inner surface of the rear wall, and the main body 1includes an image forming unit located on the imaging plane 3 a. Morespecifically, the image forming unit is configured by a Charge CoupledDevice (CCD) 3 supported by a supporting member 16 in the inner space ofthe main body 1. The imaging lens device 2 located in the projectingposition provides an imaging light beam path 10 for leading incidentlight beam to the imaging plane 3 a.

In the front wall of the main body 1, a self-timer lamp 4, a view finder5 of a finder unit, an electronic flash 6, etc. are provided. And, inthe rear wall, a liquid-crystal monitor display 7, a viewfinder eyepiece(not shown), a mode section button (not shown), a zooming operationbutton (not shown), etc. are provided. Further, in the upper wall of themain body 1, a power switch 8 and a shutter release 9 are provided. And,in the bottom wall of the main body 1, a memory card slot for insertingand ejecting a memory card, which is used for recording images formed onthe imaging plane 3 a, a serial interface connector for electricallyconnecting the portable apparatus to an outer device such as an personalcomputer, etc. are provided, all of which are not shown.

The imaging lens device 2 includes a plurality of lens elements, whichare arranged along and coaxial with the optical axis 10 a of the imaginglight beam path 10 for focusing the incident light on the imaging plane3 a. In this embodiment, the lens elements have a first lens element 11located most away from the imaging plane 3 a, a second lens element 12located in a side of the first lens element 11 near to the imaging plane3 a, and a third lens element 13 located most near to the imaging plane3 a, and forming a zoom lens system. The first lens element 11 has acylindrical member 11 a and a plurality of lens 11 b coaxially held inthe cylindrical member 11 a. The second lens element 12 also has acylindrical member 12 a and a plurality of lens 12 b coaxially held inthe cylindrical member 12 a. The third lens element 13 has a telescopictype cylindrical member 13 a and a plurality of lens 13 bcoaxially heldin the telescopic type cylindrical member 13 a.

More specifically, in the third lens element 13, the plurality of lens13 b are supported by a plurality of telescopic components of thecylindrical member 13 a respectively, and are coaxially movable alongthe optical axis 10 a of the imaging light beam path 10 with respect toeach other by the relative movement of the telescopic components.

At least one of the plural lens elements excluding the lens elementlocated most away from the imaging plane 3 a, that is the second lenselement 12 in this embodiment, is reciprocally rotational around arotation center located in the outside of the imaging light beam path 10between a first position, at which the at least one lens element, thesecond lens element 12 in this embodiment, is coaxially arranged in theimaging light beam path 10 as shown by a solid line in FIG. 2, and asecond position, at which the at least one lens element, the second lenselement 12 in this embodiment, is out from the imaging light beam path10 as shown by a two-dots chain line in FIG. 2. The reciprocal rotationof the second lens element 12 between the first position and the secondposition is performed by a reciprocal rotation mechanism (not shown)provided in the inner space of the main body 1. In this embodiment, theangle range of the reciprocal rotation is set at 180 degrees.

In this reciprocal rotation of the at least one lens element, the secondlens element 12 in this embodiment, the optical axis of the second lenselement 12 is moved in a plane including the optical axis 10 a of theimaging light beam path 10. An end face of the second lens element 12,which faces the first lens element 11 while the second lens element 12is located in the first position as shown by the solid line in FIG. 2,is faced in a direction opposite to the first lens element 11 while thesecond lens element 12 is located in the second position as shown by thetwo-dots chain lines in FIG. 2. And, the second lens element 12approaches to the finder unit when the second lens element 12 is rotatedfrom the first position to the second position.

In this embodiment, the rotation center of the second lens element 12 isconfigured by a rotational center shaft 14 supported on the outer mosttelescopic component of the telescopic type cylindrical member 13 a witha shaft position adjustment mechanism 15. The shaft position adjustmentmechanism 15 supports the rotational center shaft 14 in the outside ofthe imaging light beam path 10 to make the rotational center shaft 14cross the plane including the optical axis 10 a of the imaging lightbeam path 10 at right angles. The shaft position adjustment mechanism 15can adjust the position of the rotational center shaft 14 in a directionalong and in parallel with the optical axis 10 a of the imaging lightbeam path 10.

The imaging lens device 2 further includes a base cylindrical member 17,which is accommodated in the inner space of the main body 1, and atelescopic type cylindrical unit 18, which is telescopically connectedto the base cylindrical member 17. The base cylindrical member 17 andthe telescopic type cylindrical unit 18 are eccentrically arranged tothe optical axis 10 a of the imaging light beam path 10. The basecylindrical member 17 has a diameter surrounding the third lens element13, the first and second positions of the second lens element 12, thefirst lens element 11 and the shaft position adjustment mechanism 15with the rotational center shaft 14, and the base end of the basecylindrical member 17 is fixed to the supporting member 16. The forwardend of the base cylindrical member 17 is supported by the inner surfaceof the front wall of the main body 1 to be coaxial with the hole forprojecting the imaging lens device 2, the hole being formed in the frontwall.

The third lens element 13 is fixed to the base cylindrical member 17such that the distance between the lens located nearest to the imagingplane 3 a in the third lens element 13 and the imaging plane 3 a is setto the predetermined distance.

The telescopic type cylindrical unit 18 has two telescopic cylinders 18a and 18 b, each having a diameter surrounding the third lens-element13, the first and second positions of the second lens element 12, thefirst lens element 11 and the shaft position adjustment mechanism 15with the rotational center shaft 14. The longitudinal length of each ofthe two telescopic cylinders 18 a and 18 b is shorter than that of thebase cylindrical member 17, and the telescopic movements of the twotelescopic cylinders 18 a and 18 b relative to the base cylindricalmember 17 is caused by a cam drive mechanism (not shown) accommodated inthe inner space of the main body 1.

The forward cylinder 18 a has a forward end wall, in which an opening isformed to be coaxial with the optical axis 10 a of the imaging lightbeam path 10.

The opening allows the light beam to be lead from the outside of thetelescopic type cylindrical unit 18 into the inside thereof along theoptical axis 10 a of the imaging light beam path 10. The first lenselement 11 is fixed to the forward cylinder 18 a such that the firstlens element 11 is arranged to be coaxial with the opening of theforward end wall of the forward cylinder 18 a.

In this embodiment, a lens cover not shown is provided on the innersurface of the forward end wall of the forward cylinder 18 a. The lenscover is moved between a closed position, at which the lens cover closesthe opening of the forward end wall of the forward cylinder 18 a, and anopening position, at which the lens cover opens the opening thereof, bya lens cover driving mechanism not shown, in response to the reciprocalmovement of the telescopic type cylindrical unit 18 between theprojecting position and the retracted position. Concretely, the lenscover is located in the closed position when the telescopic typecylindrical unit 18 is located in the retracted position, and the lenscover is located in the opening position when the telescopic typecylindrical unit 18 is located in the projecting position.

In the followings, an operation of the above described thin type digitalcamera as the portable apparatus having an imaging function andaccording to one embodiment of the present invention will be described.

While the digital camera is not used for photographing, the power switch8 is turned off or the mode selection key is operated to select any oneof various modes excluding a photographing mode such as an imagemonitoring mode for displaying an image, which has been photographed, onthe monitor display 7, and an image outputting mode for outputting adata of the image, which has been photographed, to the outer device in astate that the power switch 8 has been turned on. In this time, thesecond lens element 12 is located in the second position and the firstlens element 11 together with the telescopic type cylindrical unit 18 islocated in the retracted position in the inner space of the main body 1as shown in FIG. 3. The first lens element 11 together with thetelescopic type cylindrical unit 18 has been moved to approach to theimaging plane 3 a and arranged in the first position of the second lenselement 12 to shorten the distance between the first lens element 11 andthe imaging plane 3 a. And, the lens cover not shown has closed theopening in the forward end wall of the forward cylinder 18 a to preventan outer force from being applied thereto through the opening so thatthe first lens element 11 is protected from the outer force. Further,the outer surface of the forward end wall of the forward cylinder 18 ahas been flat with the outer surface of the front wall of the main body1.

In order to use the digital camera for photographing, the power switch 8is turned on or the mode selection key is operated to select thephotographing mode in the state that the power switch 8 has been turnedon. At this time, the telescopic type cylindrical unit 18 is moved fromthe retracted position as shown in FIG. 3 to the projecting position asshown in FIGS. 1 and 2 by the cam drive mechanism (not shown), and isprojected from the front wall of the main body 1. Further, the lenscover (not shown) is moved from the closed position to the openingposition, and the first lens elements 11 is moved outward from the firstposition of the second lens element 12 and away from the imaging plane 3a. After the first lens elements 11 reaches at its most outwardlyprojected position, the second lens element 12 is moved from the secondposition as shown by the two-dots chain line in FIG. 2 to the firstposition as shown by the solid line in FIG. 2 by the reciprocal movementdriving mechanism (not shown) with the forward movement of the firstlens elements 11.

When the second lens element 12 is located in the first position, thefirst lens element 11, the second lens element 12 and the third lenselement 13 form the zoom lens system.

Then, when the shutter release 9 is pushed to its half stroke, at leastone of the lens in the third lens element 13 is moved along the opticalaxis 10 a by moving at least one of the plurality of telescopiccomponents of the cylindrical member 13 a and/or the second lens element12 is moved along the optical axis 10 a by the shaft position adjustmentmechanism 15, so that an object can be focused on the imaging plane 3 a.Further, when the shutter release 9 is pushed to its full stroke, theimage of the object focused on the imaging plane 3 a is stored in thememory card accommodated in the main body through the image forming unitsuch as the CCD.

When the zooming operation button (not shown) is operated, thetelescopic type cylindrical unit 18 together with the first lens element11 is telescopically moved along the optical axis 10 a to change theangle of view of the zoom lens system. And, at the same time, at leastone of the lens in the third lens element 13 is moved along the opticalaxis 10 a by moving at least one of the plurality of telescopiccomponents of the cylindrical member 13 a and/or the second lens element12 is moved along the optical axis 10 a by the shaft position adjustmentmechanism 15, so that an object can be focused on the imaging plane 3 a.

When the power switch 8 is turned off or the mode selection key isoperated to select any one of various modes excluding the photographingmode such as the image monitoring mode and the image outputting mode inthe state that the power switch 8 has been turned on during thetelescopic type cylindrical unit 18 is located in the projectingposition, at first the telescopic type cylindrical unit 18 together withthe first lens element 11 is moved to its most outwardly projectedposition to move the first lens element 11 fully away from the firstposition of the second lens element 12. Then, the second lens element 12is moved from the first position as shown by the solid line in FIG. 2 tothe second position as shown by the two-dots chain line in FIG. 2, andthe telescopic type cylindrical unit 18 together with the first lenselement 11 is moved to its retracted position as shown in FIG. 3.

AS apparent from the above description, since the rotational centershaft 14 functioning the rotational center of the second lens embodiment12 is located in the outside of the imaging light beam path 10 to crossthe plane including the optical axis 10 a of the imaging light beam path10 at right angles, the distance between the optical axis of the secondlens element 12 and the rotational center shaft 14 will not changeduring the reciprocal rotation of the second lens element 12 around therotational center shaft 14 between the first position and the secondposition. Therefore, when the second lens element 12 is rotated from thesecond position to the first position, the second lens element 12 isalways surely arranged in coaxial with the optical axis 10 a of theimaging light beam path 10 at its first position with high accuracy.

Further, since the second lens element 12 is rotated from the firstposition to the second position when the digital camera is not used forphotographing, the first lens element 11 can be moved to the firstposition of the second lens element 12 to shorten the distance betweenthe first lens element 11 and the imaging plane 3 a in the inner spaceof the main body 1 in comparison with that when the second lens element12 is located in the first position.

More further, since the end face of the second lens element 12, whichfaces the first lens element 11, while the second lens element 12 islocated in the first position, is faced in a direction opposite to thefirst lens element 11 while the first lens element 11 is located in thesecond position, the second position of the second lens element 12 willnot largely project forward from the first position in the directionalong the optical axis 10 a of the imaging light beam path 10. Thismakes the longitudinal length of the imaging lens device 2 being moreshorten while the digital camera is not used for photographing.

The connecting point of the second lens element 12 to the rotationalcenter shaft 14 in the direction along the optical axis 10 a may bechanged so that the location of the second position of the second lenselement 12 relative to the first position thereof in the direction alongthe optical axis 10 a may be changed.

In this embodiment, since each of the two telescopic cylinders 18 a and18 b of the telescopic type cylindrical unit 18 has the diametersurrounding the third lens element 13, the first and second positions ofthe second lens element 12, the first lens element 11 and the shaftposition adjustment mechanism 15 with the rotational center shaft 14,the two telescopic cylinders 18 a and 18 b of the telescopic typecylindrical unit 18 will not collide with the third lens element 13, thesecond lens element 12 whether it is located in the first position or inthe second positions, the first lens element 11 and the shaft positionadjustment mechanism 15 with the rotational center shaft 14, when eachof the two telescopic cylinders 18 a and 18 b is located in theretracted position. This makes the longitudinal length of the telescopictype cylindrical unit 18 when each of the two telescopic cylinders 18 aand 18 b is located in the retracted position being shorten, and furthermakes the size of the main body 1, in which the retracted two telescopiccylinders 18 a and 18 b of the telescopic type cylindrical unit 18 areaccommodated, in the direction along the optical axis 10 a beingshorten.

Therefore, when the two telescopic cylinders 18 aand 18 b of thetelescopic type cylindrical unit 18 are located in the retractedposition, they are fully accommodated in the inner space of the mainbody and will not project from the main body 1 so that the outer surfaceof the main body 1 can be smooth to improve the portability of thedigital camera while it is not used for photographing.

The telescopic type cylindrical unit 18 has the two telescopic cylinders18 a and 18 b in this embodiment, but the telescopic type cylindricalunit 18 may have only one telescopic cylinder, three or more than threetelescopic cylinders.

The imaging lens device 2 has the first, second and third lens elements11, 12 and 13 in this embodiment, but the imaging lens device 2 may havetwo, four or more than four lens elements.

The second lens element 12 is reciprocally rotational between the firstposition and the second position in this embodiment, but the lenselement, which is located nearest to the imaging plane 3 a in theplurality of lens elements of the imaging lens device 2 and whichcorresponds to the third lens element 13 in this embodiment, in place ofthe second lens element 12 may be reciprocally rotational between thefirst position and the second position around the rotational centerlocated in the outside of the imaging light beam path 10 d lens element12. In this case, after the lens element, which is located nearest tothe imaging plane 3 a and which corresponds to the third lens element 13in this embodiment, is moved from the first position to the secondposition, the remaining lens elements, which correspond to the first andsecond lens elements 11 and 12, are moved to the first position of thelens element, which is located nearest to the imaging plane 3 a andwhich corresponds to the third lens element 13 in this embodiment, toshorten the longitudinal length of the second lens element 12 along theoptical axis 10 a of the imaging light beam path 10. And, thereciprocally rotational angle range of the lens element, which islocated nearest to the imaging plane 3 a and which corresponds to thethird lens element 13 in this embodiment, may be 90 degrees.

The plurality of lenses of the third lens element 13, which is locatednearest to the imaging plane 3 a, are movable along the optical axis 10a of the imaging light beam path 10 relative to each other in thisembodiment, but the third lens element 13 may have only one lens, whichis movable along the optical axis 10 a to focus the incident light beamon the imaging plane 3 a.

Further, the portable apparatus having an imaging function is the thintype digital camera in this embodiment, but the portable apparatusaccording to the present invention may be another type of digitalcamera, a normal camera using a film as an image recording medium, amobile phone with a digital camera, etc.

Additional advantages and modifications will readily occur to thoseskilled in the art. Therefore, the invention in its broader aspects isnot limited to the specific details and representative embodiment shownand described herein. Accordingly, various embodiments may be madewithout departing from the spirit or scope of the general inventiveconcept as defined by the appended claims and their equivalents.

1. An imaging lens device, which provides an imaging light beam path forleading incident light beam to a predetermined imaging plane andincludes a plurality of lens elements arranged along and being coaxialwith the imaging light beam path for focusing the incident light beam onthe predetermined imaging plane, at least one of the plural lenselements excluding a lens element located most away from thepredetermined imaging plane, being reciprocally rotational around arotation center located in the outside of the imaging light beam pathbetween a first position, at which the at least one lens element iscoaxially arranged in the imaging light beam path, and a secondposition, at which the at least one lens element is out from the imaginglight beam path, the most away located lens element being reciprocallymovable along the imaging light beam path, and the most away locatedlens element being moved to approach to the predetermined imaging planewhile the at least one lens element is located in the second position,and shortening a distance between the most away located lens element andthe predetermined imaging plane in comparison with the distance betweenthem when the at least one lens element is located in the firstposition.
 2. The imaging lens device according to claim 1, wherein anoptical axis of the at least one lens element moves in a plane includingan optical axis of the imaging light beam path while the at least onelens element reciprocally rotates between the first position and thesecond position.
 3. The imaging lens device according to claim 1,wherein the plural lens elements includes a first lens element being themost away located lens element, a second lens element located in a sideof the first lens element near to the predetermined imaging plane andbeing the at least one lens element, and a third lens element locatedmost near to the predetermined imaging plane.
 4. The imaging lens deviceaccording to claim 1, wherein an end face of the at least one lenselement, which faces the most away located lens element, while the atleast one lens element is located in the first position, is faced in adirection opposite to the most away located lens element while the atleast one lens element is located in the second position.
 5. The imaginglens device according to claim 1, further comprising a cylindrical unit,which has a diameter surrounding the first and second positions of theat least one lens element and is reciprocally movable along the opticalaxis of the imaging light beam path, and to which the most away locatedlens element is mounted so that the most away located lens elementtogether with cylindrical unit is reciprocally movable along the opticalaxis of the imaging light beam path.
 6. The imaging lens deviceaccording to claim 1, wherein at least one of the plural lens elementshas a plurality of lens.
 7. A portable apparatus having an imagingfunction, comprising: a portable apparatus main body having an innerspace accommodating an imaging plane; and an imaging lens device, whichprovides an imaging light beam path for leading incident light beam tothe imaging plane and includes a plurality of lens elements arrangedalong and being coaxial with the imaging light beam path for focusingthe incident light beam on the imaging plane, at least one of the plurallens elements excluding a lens element located most away from theimaging plane, being reciprocally rotational around a rotation centerlocated in the outside of the imaging light beam path between a firstposition, at which the at least one lens element is coaxially arrangedin the imaging light beam path, and a second position, at which the atleast one lens element is out from the imaging light beam path, theimaging lens device including a cylindrical unit being provided with themost away located lens element, having a diameter surrounding the firstand second positions of the at least one lens element, and beingreciprocally movable together with the most away located lens elementalong the optical axis of the imaging light beam path, and the most awaylocated lens element being moved to approach to the imaging plane whilethe at least one lens element is located in the second position, andshortening a distance between the most away located lens element and theimaging plane in comparison with the distance between them when the atleast one lens element is located in the first position.
 8. The portableapparatus according to claim 7, wherein the cylindrical unit togetherwith the most away located lens element is moved into the inner space ofthe portable apparatus main body when the most away located lens elementis moved to approach to the imaging plane while the at least one lenselement is located in the second position, and the cylindrical unittogether with the most away located lens element is moved out from theinner space of the portable apparatus main body when the most awaylocated lens element is moved away from the imaging plane for rotatingthe at least one lens element from the second position to the firstposition.
 9. The portable apparatus according to claim 7, wherein anoptical axis of the at least one lens element moves in a plane includingan optical axis of the imaging light beam path while the at least onelens element reciprocally rotates between-the first position and thesecond position.
 10. The portable apparatus according to claim 7,wherein the plural lens elements includes a first lens element being themost away located lens element, a second lens element located in a sideof the first lens element near to the imaging plane and being the atleast one lens element, and a third lens element located most near tothe imaging plane.
 11. The portable apparatus according to claim 7,wherein an end face of the at least one lens element, which faces themost away located lens element while the at least one lens element islocated in the first position, is faced in a direction opposite to themost away located lens element while the at least one lens element islocated in the second position.
 12. The portable apparatus according toclaim 7, wherein at least one of the plural lens elements has aplurality of lens.
 13. The portable apparatus according to claim 7,wherein the portable apparatus main body further includes an imageforming unit located on the imaging plane.
 14. The portable apparatusaccording to claim 7, wherein the portable apparatus main body furtherincludes a finder unit, and the at least one lens element approaches tothe finder unit when the at least one lens element is rotated from thefirst position to the second position.